1. Field of the Invention
The present invention relates to devices for increasing the density of air intake in internal combustion engines, and more particularly to a multi-stage centrifugal air pump that acts as a replacement for a conventional radiator fan, while at the same time having a high air density output applied to the air intake to effectively operate as a supercharger.
2. Description of the Related Art
Increasing the mass of air into a cylinder of an internal combustion engine will increase its output. By increasing the piston size and its displacement the volume of air will increase. To increase the output at a given volume of air, the density of the charged air must be increased. Air density may be increased by supercharging or turbocharging. Turbochargers use exhaust gas heat pressure to rotate a hot gas turbine, which in turn rotates an air compressor turbine. There are two types of superchargers, axial flow and centrifugal flow. Axial flow superchargers are also know as positive displacement superchargers. Superchargers typically increase the density of air three or four times its original density.
There is a serious drawback to turbochargers in that they are effectively operational at one third of redline round per minute (rpm), which means that it will take time to build up exhaust gas and to rotate the compressor turbine. There is no sizeable increase in air density at low rpm, so there is no increase in output at low rpm. This is referred to as the turbocharging gap. Another drawback is that exit air temperature is relatively higher due to the hot turbine environment. Also, turbochargers require elaborate manufacturing and maintenance that will translate into higher costs to consumers.
Superchargers are driven by a small pulley that is belted to a relatively larger pulley that is in turn attached to a crankshaft of an engine. The pulleys will accelerate the rpm of the supercharger in relation to the rpm of the crankshaft. Both positive displacement and centrifugal superchargers will effectively increase air density at high rpm. Any increase in engine revolution, with no gap, will increase the supercharger revolution but full effectiveness is at high revolution. Superchargers also require high manufacturing and maintenance.
Various engine systems with turbochargers, superchargers and other air cooling devices are known or have been proposed.
U.S. Pat. No. 4,010,613, issued Mar. 8, 1977 to Charles E. McInerney, discloses a turbocharged engine after cooling system. The turbocharged engine air supply cooling arrangement utilizes an air-to-air heat exchanger provided with a fan to circulate ambient air about the heat exchanger to cool the compressor discharge air. The air is cooled to near the temperature of the ambient air as it passes through the heat exchanger. The air is then conveyed through a turbine. As the air passes through the turbine it is cooled to a temperature that is lower than the temperature of the ambient air.
U.S. Pat. No. 4,907,552, issued Mar. 13, 1990 to Chans A. Martin, shows a forced air induction system. The forced air system is provided in an air box of an ATV. A fan is installed in the air box next to an enlarged air inlet. The fan sucks air into the box and pushes air through the air box and through an air filter to a downstream carburetor. The pressurized air produces a boost in power acting as a supercharger for the ATV to increase the horsepower of the ATV.
U.S. Pat. No. 4,918,923, issued Apr. 24, 1990 to William E. Woollenweber et al., teaches an internal combustion engine turbosystem. The invention is an exhaust-driven cooling system for an internal combustion engine that includes a turbocooler having an exhaust-driven turbine and ducted fan means to generate a flow of cooling air for use in an internal combustion engine heat exchanger to dissipate heat loss of the engine. The system also provides a control for the generation of cooling air. The system provides internal combustion engines with reduced temperatures and pressures for its exhaust gas.
U.S. Pat. No. 5,787,711, issued Aug. 4, 1998 to William E. Woollenweber et al., describes a motor-assisted turbo-cooling system for internal combustion engines. The internal combustion cooling system incorporates a motor-assisted turbofan. The turbine driven fan is increased in rotational speed by energizing a motor attached to the turbine fan shaft from an outside power source to provide required cooling air flow. The cooling air system of the invention includes a duct fan for supplying cooling air for one or more heat exchangers and is controlled by a system of sensors.
Other devices are described in U.S. Patent Publication No. 2002/0162318, published Nov. 7, 2002 (bimodal fan, heat exchanger and bypass air supercharging for piston or rotary driven turbine); U.S. Patent Publication No. 2002/0189255, published Dec. 19, 2002 (combined remote first intake air aftercooler and a second fluid from an engine cooler for an engine); U.S. Pat. No. 2,099,785, issued Nov. 23, 1937 to A. V. D. Willgoos (engine intake system); U.S. Pat. No. 2,839,038, issued Jun. 17, 1958 to C. E. Middlebrooks, Jr. (supercharger for internal combustion engine); U.S. Pat. No. 4,319,554, issued Mar. 16, 1982 to A. E. Buffie (fuel system for internal combustion engines); and U.S. Pat. No. 4,846,258, issued Jul. 11, 1989 to H. N. Charles (non-ram cooling system).
Japanese Patent No. 57-46,012, published Mar. 16, 1982, discloses a supercharger cooling device for an engine. The cooling device enhances the filling efficiency of an engine by providing a supercharger, consisting of a compressor arranged in the suction line of the engine, with a rotary radiating member driven by the shaft of the supercharger, which cools the compressor. The turbo-supercharger is composed of a compressor and a turbine. A cooling fan is fixed to the extended end of a shaft to cool a compressor impeller. The supercharger and the radiator are cooled together. Thus the filling efficiency of the engine can be enhanced and the durability of the supercharger improved.
United Kingdom Patent No. 2,147,356, published May 9, 1985, shows supercharging a motor vehicle internal combustion engine. A charge-air compressor for supercharging an engine is driven by a turbine. The turbine is driven by means of air collected by an air scoop during forward movement of the vehicle. Some of the air may be supplied to the engine through a passage that bypasses the carburetor. The turbine cools the air drawn into the engine.
United Kingdom Patent No. 2,154,280, published Sept. 4, 1985, teaches an engine-driven positive displacement supercharger. The supercharger is driven through a belt from a pulley attached to an extension of the engine crankshaft by a free wheel hub. In operation, air enters a rotor through a rotatably adjustable valve. The air charge is expanded to fill the entire workspace and is later re-compressed to a volume matching that of the engine and delivered through an exchanger to the engine cylinders. Fuel may be injected into the air charge before, during or after the supercharger without departing from the desired effects of the invention.
European Patent No. 849,447, published Jun. 24, 1998, describes an arrangement for the indirect cooling of an internal combustion engine or a motor coach. The cooling system has an air-fluid heat exchanger in which the fluid flow is cooled by a forced air flow produced by a fan. The fan is in the form of a centrifugal turbine with its axis of rotation and axial intake lying perpendicular to a first wall, and its centrifugal outlet flow channeled so that it exits tangentially and perpendicular a second wall. Finally, European Patent No. 343,785, published Nov. 11, 1989, teaches a cooling system for an internal combustion engine.
None of the above inventions disclose a device that can increase the density of air at low engine rpm. None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. Thus, a radiator cooling fan replacement to increase engine efficiency solving the aforementioned problems is desired.